The present invention relates to a thread break detector for a sewing machine.
It is known to use thread break detectors in sewing machines to monitor the sewing threads. Such thread break detectors are known from, for example, West German Patent Specification No. 35 01 387 and East German Patent Specification No. 228 843. West German Patent Specification No. 35 01 387 describes a thread break detector which monitors a plurality of sewing threads, and in which it is not possible to monitor one single sewing thread. Furthermore, the sewing threads are guided through a sensing arm, and are additionally deflected. East German Specificiation No. 228 843 relates to a contactless thread break detector in which the thread oscillations generated during the sewing operation are used as signal generators. As sewing threads of different materials and varying elasticity are used for sewing, and the oscillation amplitude of the sewing thread is dependent on the thread material and elasticity and on the sewing speed, it is not possible to transmit an unambiguous signal.